Bug#1043073: xmobar: Battery monitor ignores "on" status string

[Nick]

Package: xmobar
Version: 0.46-1
Severity: normal

After upgrading to Debian 12, xmobar ignores the value for the -O
option in the battery monitor.  From my config,

      Run BatteryN ["BAT0"]
              ["-t", "<left><acstatus>",
               "-L", "30", "-H", "74",
               "-l", "red", "-n", "orange", "-h", "yellow",
               "-S", "on",
               "--", "-O", "<fc=green>▲</fc>", "-i", "<fc=cyan>=</fc>",
               "-o", "<fc=yellow>▼</fc>"]
              30 "bat0",

This worked for several years, in that "▲" would appear while the
battery is charging but now it's blank.  The strings for the other
states ("=" and "▼" in my case) do still appear as expected.

Please let me know if I can provide more information.
Thanks

-- System Information:
Debian Release: 12.1
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 6.1.0-10-amd64 (SMP w/4 CPU threads; PREEMPT)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages xmobar depends on:
ii  libasound2           1.2.8-1+b1
ii  libc6                2.36-9+deb12u1
ii  libcairo2            1.16.0-7
ii  libffi8              3.4.4-1
ii  libglib2.0-0         2.74.6-2
ii  libgmp10             2:6.2.1+dfsg1-1.1
ii  libharfbuzz0b        6.0.0+dfsg-3
ii  libiw30              30~pre9-14
ii  libpango-1.0-0       1.50.12+ds-1
ii  libpangocairo-1.0-0  1.50.12+ds-1
ii  libx11-6             2:1.8.4-2+deb12u1
ii  libxext6             2:1.3.4-1+b1
ii  libxft2              2.3.6-1
ii  libxinerama1         2:1.1.4-3
ii  libxpm4              1:3.5.12-1.1
ii  libxrandr2           2:1.5.2-2+b1
ii  libxrender1          1:0.9.10-1.1
ii  libxss1              1:1.2.3-1
ii  zlib1g               1:1.2.13.dfsg-1

xmobar recommends no packages.

Versions of packages xmobar suggests:
ii  xmonad  0.17.1-1

-- no debconf information